The present invention relates to an automotive vehicle with a continuously variable transmission, and more particularly to a ratio control for such a transmission during braking.
U.S. Pat. No. 4,735,113 issued on Apr. 5, 1988 to Yamamuro et al. discloses a ratio control wherein a target value in a reduction ratio dependent variable (a turbine revolution speed) is derived by table look-up of a predetermined shift pattern data based on a wheel speed indicative signal generated by a vehicle speed sensor arranged on a transmission output member drivingly coupled with a driving road wheel and an engine load indicative signal generated by a throttle sensor. During braking, by depression of a brake pedal wherein the wheel speed deviates from the actual vehicle speed, a shift toward the maximum reduction ratio results due to a drop in the wheel speed. This hampers quick recovery of the wheel speed after the brake pedal is released subsequently.
An object of the present invention is to improve a ratio control for a continuously variable transmission such that a quick recovery of wheel speed of a driving road wheel is assured upon release of a brake pedal after braking.